1. Field
The field of the invention relates to instruments for performing optical power measurements of an eye.
2. Description of the Related Art
The human eye includes a cornea and a crystalline lens that are intended to focus light that enters the pupil of the eye onto the retina. However, the eye may exhibit various refractive errors which result in light not being properly focused upon the retina, and which may reduce visual acuity. Ocular aberrations can range from the relatively simple spherical and cylindrical errors that cause myopia, hyperopia, or regular astigmatism, to more complex refractive errors that can cause, for example, halos and starbursts in a person's vision.
Many interventions have been developed over the years to correct various ocular aberrations. These include sphero-cylindrical corrective optical elements, such as spectacles, contact lenses, and intraocular lenses (IOLs), or corneal refractive surgery, such as LASIK. The diagnosis and correction of ocular aberrations typically involves the use of an optical power measurement device to determine the optical power of the eye. Although many different types of objective optical power measurement devices have been created, simpler, less-expensive objective optical power measurement devices may be beneficial.